The present invention relates to the general field of aviation turbine engines, and in particular turbojets. It relates more particularly to a link part having a radial retention function, such as a fan ferrule providing mechanical and aerodynamic connection between a fan inlet cone, fan blade platforms constituting the inside of the flow section between the fan blades, and a fan disk.
At its upstream end, a turbojet has an air inlet feeding a fan and a compressor having blades that are carried by disks secured to a rotor shaft that extends over a major portion of the turbojet and that is driven in rotation by a turbine of the turbojet.
An inlet cone is mounted on the upstream end of this platform in order to deflect a fraction of the air stream that penetrates into the turbojet towards the fan blades, this stream subsequently being separated into a primary stream that feeds the gas generator and a secondary stream that provides the majority of the thrust from the engine.
In the prior art, the inlet cone is securely mounted at the end of the platform and its shape and dimensions are determined so as to optimize the incidence of air on the roots of the fan blades for a given stage of flight, the inlet cone also needing to deflect particles or solid matter outwards and to constitute protection against ingesting ice.
The connection with the fan platform is subjected both to mechanical strength constraints and to aerodynamic performance constraints. The present metal-based technologies penalize the weight of the low pressure rotor line, while incorporating an aerodynamic contouring (3D flow section) function also penalizes the cost of fabrication. Furthermore, existing composite connections do not incorporate the function of radially retaining adjacent parts. It should be observed that this radial retention function applies mainly in conditions of accidental operation after ingesting a foreign body or losing a fan blade (the effect of dynamic reactions of the blade connected thereto during the transient phenomenon).
Selecting a structure that is appropriate for this link part thus depends on a compromise between those two relatively contradictory constraints, and prior art structures do not provide a genuinely satisfactory solution to those two constraints.